Strap tensioner device with fulcrum means for pivotal removal of the device



p 1965 D. T. ARMINGTON 5 3,206,167

STRAP TENSIONER DEVICE WITH FULGRUM MEAN FOR PIVOTAL REMOVAL OF THE DEVICE Filed Nov. 7, 1963 2 Sheets-Sheet l INVENTOR DONALD T. ARMINGTON BYM7, WW Miw ATTORNEYS Sept. 14, 1965 D. 'r. ARMINGTON 3,206,167

STRAP TENSIONER DEVICE WITH FULORUM MEANS FOR PIVOTAL REMOVAL OF THE DEVICE Filed Nov. 7, 1963 2 Sheets-Sheet 2 INVENTOR. DONALD T. ARM l NGTON ATTORNEYS United States Patent STRAP TENSIDNER DEVICE WITH FULCRUM MEANS FOR PIVOTAL REMOVAL OF THE DEVICE Donald T. Armington, Southington, Conn., assignor to The Stanley Works, New Britain, Conn., a corporation of Connecticut Filed Nov. 7, 1963, Ser. No. 322,166 4 Claims. (Cl. 254-51) The present invention relates to strap tensioners of the type useful in conjunction with a strap sealer for applying a tensioned strap to an article or package and more specifically to a strap tensioncr having particular utility for tensioning a strap about a substantially noncompressible, irregular, or fragile article, such as a conventional TV picture tube. When the article to be strapped is noncompressible, irregular or fragile it may be desirable, in order to provide the optimum residual tension in the sealed strap, to draw the strap taut about the article with the strap tensioncr, to seal the tensioned loop of strap, and to remove the strap tensioncr from the sealed loop of tensioned strap, all without substantially overstressing the strap above the desired residual tension and without placing an undue force upon the article. The present invention is accordingly directed to a new and improved strap tensioncr which allows for applying a tensioned loop of strap to an article with minimum overstressing of the strap and which includes a fulcrum device for pivotal removal of the strap tensioncr from the sealed loop of strap without overstressing the strap or applying undue force on the article.

It is a primary aim of the present invention to provide a new and improved strap tensioncr which can be readily removed after a strap has been tensioned and sealed about an article even though the article is fragile or substantially noncompressible. Included in this aim is the provision of an improved strap tensioncr of the type having a base positioned between the strap and the article while the strap is being applied to the article which can be readily withdrawn from beneath the tensioned and sealed strap without further stressing the strap or applying additional pressure to the article.

It is another object of the present invention to provide a strap tensioner which can be manually manipulated for tensioning a strap and which can be conveniently manually withdrawn from the tensioned strap after it has been sealed to the article.

Other objects will be in part obvious and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangement of parts which will be exemplified in the construction hereafter set forth, and the scope of the application of which will be indicated in the appended claims.

In the drawings:

FIG. 1 is a perspective view, partly broken away, of an embodiment of a strap tensioncr of the present invention;

FIG. 2 is an enlarged partial side view, partly broken away, of the strap tensioncr showing overlapping portions of an untensioned strap inserted therein;

FIG. 3 is an enlarged partial side view similar to FIG. 2 showing the overlapping portions of strap in a tensioned configuration;

FIG. 4 is a front view, partly broken away and partly in section, of the strap tensioncr showing it at an intermediate stage of removal from a tensioned strap;

FIG. 5 is a partial section view taken substantially along line 55 of FIG. 2; and

FIG. 6 is a perspective view of an installation of the strap tensionerand a strap sealer for application of a strap about a conventional TV picture tube.

Referring now to the drawings in more particularity, a preferred embodiment of a strap tensioncr of the present invention, generally denoted by the numeral 10, comprises a conventional rotary air motor 12 suitably secured to a housing 14 which, in a well-known manner, encases a speed reducer for drivingly connecting the air motor 12 with a serrated friction wheel 16 to rotatably drive the wheel counterclockwise as viewed in FIG. 3. The friction wheel 16 has a drive shaft (not shown) rotatably mounted in a bearing 18 in a side plate 20 which is fixed to an integral lateral extension 22 of the housing 14.

A pivot plate 24 is piovtally connected to the housing 14 between the side plate 20 and housing 14 by a fixed pivot pin 26 extending therebetween, for which purpose the pivot plate is provided with an arcuate slot (not shown) receiving the friction wheel shaft. The pivot plate 24 is pivotally biased, counterclockwise as viewed in FIG. 3, by a torsion spring 28 which encircles the pivot pin 26 and which has elongated legs 30, 32 in engagement with the lateral housing extension 22 and with a lug 34, respectively, which lug 34 is integrally formed with the pivot plate 24. For limiting the pivotal movement of the plate 24 under the bias of the torsion spring 28 an adjustable stop 36 (FIG. 2) is threaded into the plate 24 for engagement with a hardened element 38 fixed to the housing 14. For pivoting the plate against the bias of torsion spring 28, clockwise as seen in FIG. 2, there is provided a rearwardly extending handle 39 fixed to the plate 24 which can be conveniently manually actuated while manipulating the tensioner.

In accordance with the present invention, the pivot plate 24 is provided with an integral elongated narrow base 40 located adjacent to and beneath the friction wheel 16. The base 40 has a generally planar base surface 41 adapted for engagement with the article to which a strap is being applied. The outer surface of the base 40 is longitudinally tapered from adjacent the friction wheel 16 to provide a forward ramp 42 and a rear ramp 44 which extend generally parallel to the axis of rotation of the friction wheel. Intermediate the forward and rear ramps and fixed in a lateral groove in the base is a hardened insert 46 which can be conveniently removed from the base by removing a retaining screw 48. The insert 46 is positioned for cooperation with the friction wheel 16 for retaining the inner lap of strap 50 against longitudinal slippage on the base while the tension wheel is advancing the outer lap of strap 52, to .the right as seen in FIGS. 2, 3 and 6, for which purpose, the insert 46 is provided with forwardly facing lateral serrations extending substantially parallel to the axis of the friction wheel 16, and the friction wheel 16 is provided with similar rearwardly facing serrations which, however, are inclined to the wheel axis, clockwise as seen in FIGS. 2 and 3, whereby as a result the overlapping portions of the strap are urged inwardly against the pivot plate 24 for maintaining them in proper relationship with the tension wheel during the tensioning operation. Accordingly, the pivot plate 24 provides for longitudinally guiding the laps of strap with respect to the strap tensioncr, which guidance is assisted by a rear strap guide 54 formed from sheet metal and secured to the housing extension 22 as by fasteners 56. The axis of rotation of the friction wheel 16 and the axis of pivotal movement of the pivot plate 24 are related so that the frictional force between the inner and outer laps of strap assists the torsion spring 28 in clamping the laps and thereby increase the effectiveness of the serrated surfaces of the tension wheel 16 and insert 46.

In accordance with a principal aspect of the present invention, a forward fulcrum plate is mounted for reciprocable movement on the pivot plate 24 substantially normal to the planar base surface 41 by a pair of fasteners 68 and by a channel guideway 71 in the pivot plate 24 which receives a cooperating projection 72 of the plate 60. The fasteners 68 are received within elongated slots 70 in the fulcrum plate and thereby provide for limiting the reciprocable movement of the plate. The fulcrum plate is urged inwardly to its lower limit or extended position shown in FIG. 4 by a pair of leaf springs 74 having their forward ends overlapping the upper edge of the plate and their rear ends fixed .to the handle 39 by fasteners 76. A lower lateral corner of the fulcrum plate is cut out at 62 to define with the forward ramp 42 a lateral slot opening 63 adapted for receiving the untensioned overlapping portions of the strap, as shown in FIG. 2. The fulcrum plate therefore has a generally L- shapcd edge portion with a laterally extending edge 65 overlying a strap received in the opening 63 and an edge 75 extending outwardly therefrom. Accordingly, when positioning the strap about an article for tensioning, the overlapping portions of the strap are inserted within the slot opening 63 and between the friction wheel 16 and insert 46 for which purpose the pivot plate 24 may be pivoted against the bias of the torsion spring 28 by the handle 39. The strap tensioner can thereafter be manually operated by a suitable motor control 66.

For the application of a strap about an associated article the strap tensioner is operated for tensioning the strap and a conventional strap sealer is used to seal the overlapping portions of strap preferably at a point forwardly of the strap tensioner. This tensioning and sealing of the strap operates to displace the strap outwardly from the associated article and thereby separate the strap from the front and rear ramps of the base 40 with the result that the fulcrum plate 60 is raised or retracted against the bias of the leaf springs 74 as shown in FIG. 3. In this regard, the strap is displaced from the associated article principally as a result of the camming effect of the sealer jaws against the underside of the strap as they move inwardly beneath the strap for sealing.

The strap tensioner can then be manually moved to displace the base 40 from between the sealed loop of tensioned strap and the article preferably after the strap sealer is operated to withdraw the sealer jaws from beneath the strap and the sealed loop of strap is suitably sheared from the unused strap. This is accomplished by laterally pivoting the tensioner clockwise, as viewed from thereabove, to displace the lateral edge 65 of the fulcrum plate 60 out of overlying association with the sealed strap and thereby allow the leaf springs 74 to move the fulcrum plate inwardly to its lower limit, at which point the edge 75 of the fulcrum plate is disposed adjacent the lateral edge of the tensioned loop of strap as shown in FIG. 4. The strap tensioner can then be pivoted counterclockwise, as viewed from thereabove, whereby the edge 75 of the fulcrum plate 69 engages the strap edge to provide a fulcrum for displacing the base laterally from beneath the tensioned strap. Accordingly, the strap tensioner can be readily removed after the strap is tensioned and sealed without the necessity of lifting the tensioner from the article and therefore without further stressing the straps or affecting the residual tension thereof, and inasmuch as the serrations on the insert 46 extend laterally on the base and the strap is out of contact with the tampered ramps 42, 44, the lateral displacement of the tensioner from the tensioned strap is facilitated.

Referring now to FIG. 6 wherein there is shown an installation of a tensioner of the present invention and a sealer 80, which may be of any well-known variety, for use in connection with the application of a tensioned strap to a conventional TV picture tube 82. This application of a tensioned strap has been found to be useful in preventing implosion of the tube as when the face 84 of the tube is cracked or broken. Such tubes are conventionally highly vacuumized and accordingly when the tube is cracked or broken, the implosion of the tube typically results in the rearward portion 86 of the tube being drawn forwardly through the tube face with a hazardous situation resulting. It has been found, however, that by the application of a tensioned loop of strap about the tube perimeter adjacent the tube face implosion of the tube and the dangerous consequences that may result therefrom can be minimized. This result is obtained because the tensioned strap compresses the tube slightly to sufficiently force the face of the tube outwardly and the rearward portion 86 of the tube rearwardly thereby offsetting the forces released when the tube is broken; However, the tube compression and therefore the strap tension must be maintained within certain limits to be effective and yet to avoid damaging the picture tube. Accordingly, the tension applied to the strap by the tensioner must be substantially reduced after the tensioner is removed from the tube and such removal of the tensioner must be accomplished without increasing the strap tension or without bearing against the tube.

The utility and advantages of the strap tensioner of the present invention in the application of a tensioned strap to a TV picture tube should therefore be readily appreciated. The tensioner can be readily operated to tension the strap about the tube and the sealer 80 can be operated in a well-known manner .to seal the tensioned strap. Thereafter, the tensioner 10 can be readily removed merely by laterally pivoting the tensioner first clockwise and then counterclockwise during which latter pivotal movement the plate 60 provides a fulcrum for pivotal movement of the tensioner base from beneath the tensioned strap;

Moreover, as the tensioner base 40 is narrow and is merely withdrawn laterally from beneath the tensioned strap, its removal will not substantially affect the resulting residual tension of the strap.

Thus, it can be seen that the strap tensioner of the present invention provides a readily useful and convenient tool for applying a strap to a fragile or noncompressible article, as for example a TV picture tube, and which can be readily removed from the tensioned and sealed strap without thereby overtensioning the strap or forcing the base of the tensioner against the strapped article.

As will be apparent to persons skilled in the art, various modifications and adaptations of the structure above described will become readily apparent without departure from the spirit and scope of the invention, the scope of which is defined in the appended claims.

I claim:

1. In a tool for tensioning a strap about an article having, a base with a base surface engageable with the article and an outer surface portion for receiving a longtudinally extending strap, and a driven tensioning member mounted for operative engagement with the strap for forwardly feeding the strap longitudinally across the outer surface portion, the improvement wherein the tool further comprises a fulcrum member longitudinally spaced from the tensioning member rearwardly thereof having a generally L-shaped edge portion with a first laterally extending substantially straight edge part in longitudinal alignment with the outer surface portion of the base, said first edge part being positioned in overlying relationship with the strap for engagement with the outer surface thereof as the strap is tensioned by the driven tensioning member, and a second substantially straight edge part extending outwardly from a lateral end of the first edge part engageable with a lateral edge of the tension strap after the tool and has been laterally pivoted in one pivotal direction for displacing the first edge part out of said overlying relationship with the strap whereby the second edge part provides a fulcrum for the pivotal movement of the tool in the opposite pivotal direction for removal of the base from between the tensioned strap and article.

2. The improvement of claim 1 further comprising means for mounting the fulcrum member on the base for rectilinear movement in a direction outwardly of the strap,

said fulcrum member being positioned so that when the strap is tensioned the strap withdraws the fulcrum member outwardly of the base, and so that when the tool is laterally pivoted for positioning the first edge part out of said overlying relationship with the strap, the fulcrum member can be extended for engagement of the second edge part of the fulcrum member with the strap to provide a fulcrum for pivotal movement of the tool in said opposite pivotal direction.

3. In a tool for tensioning a strap about an article having, a base with a base surface engageable with the article and an outer surface portion for receiving a longitudinally extending strap, and a driven tensioning member mounted for operative engagement with the strap for forwardly feeding the strap longitudinally across the outer surface portion, the improvement wherein the tool further comprises a fulcrum member mounted for reciprocable rectilinear movement generally normal to the base surface, said fulcrum member having an L-shaped edge portion with a laterally extending first substantially straight edge part longitudinally spaced from the driven tensioning member rearwardly thereof and positioned in overlying relationship with the strap for engagement with the outer surface thereof, and a second substantially straight edge part extending outwardly from a lateral end of the first straight edge part providing a fulcrum edge for pivotal removal of the tensioning tool.

4. In a tool for tensioning a strap about an article having, a longitudinally extending base with a base surface engagable with the article and an outer surface for receiving longitudinally extending overlapping strap portions of a loop of strap and a driven tensioning member mounted for operative engagement with the outer strap portion intermediate the longitudinal ends of the base for longitudinally feeding the outer strap portion forwardly of the base, the improvement wherein the base has a laterally serrated base portion adjacent the tensioning wheel and is longitudinally tapered therefrom to provide forward and rear ramps, and wherein the tool further comprises a fulcrum member extending outwardly of the strap in overlying relationship therewith, said fulcrum member being mounted in longitudinal alignment with the serrated base portion rearwardly thereof and for reciprocable rectilinear movement outwardly therefrom between an inner extended position and an outer withdrawn position, and means for biasing the fulcrum member inwardly to its extended position, said fulcrum member having a generally L-shaped edge portion with a first laterally extending substantially straight edge part in longitudinal alignment with the serrated base portion, said first edge part being positioned in overlying relationship with the strap for engagement with the outer surface thereof as the strap is tensioned by the driven tensioning member, and a second substantially straight fulcrum edge part extending outwardly from a lateral end of the first edge part, said first edge part in the extended position of the fulcrum member defining with the forward ramp a laterally opening passage adapted for receiving untensioned strap, said fulcrum member being positioned to be Withdrawn against said bias by the strap whereby with the strap in its tensioned configuration the tool base can be laterally removed from between the strap and the article by laterally pivoting the tool in one pivotal direction for moving the first edge part of the fulcrum member out of said overlying relationship with the strap and thereafter pivot the tool in the opposite pivotal direction with the second edge part in the extended position of the fulcrum member engaging the lateral edge of the tensioned strap to provide a fulcrum for pivotal removal of the tool.

References Cited by the Examiner UNITED STATES PATENTS 1,833,168 11/31 MacChesney et al. 254-51 X 1,939,746 12/33 Whitman 25479 2,864,582 12/58 Hall 25451 2,919,894 1/60 Hepler 254-51 WILLIAM FELDMAN, Primary Examiner.

MILTON S. MEHR, Examiner. 

1. IN A TOOL FOR TENSIONING A STRAP ABOUT AN ARTICLE HAVING, A BASE WITH A BASE SURFACE ENGAGEABLE WITH THE ARTICLE AND AN OUTER SURFACE PORTION FOR RECEIVING A LONGITUDINALLY EXTENDING STRAP, AND A DRIVEN TENSIONING MEMBER MOUNTED FOR OPERATIVE ENGAGEMENT WITH THE STRAP FOR FORWARDLY FEEDING THE STRAP LONGITUDINALLY ACROSS THE OUTER SURFACE PORTION, THE IMPROVEMENT WHEREIN THE TOOL FURTHER COMPRISES A FULCRUM MEMBER LONGITUDINALLY SPACED FROM THE TENSIONING MEMBER REARWARDLY THEREOF HAVING A GENRALLY L-SHAPED EDGE PORTION WITH A FIRST LATERALLY EXTENDING SUBSTANTIALLY STRAIGHT EDGE PART IN LONGITUDINAL ALIGNMENT WITH THE OUTER SURFACE PORTION OF THE BASE, SAID FIRST EDGE PART BEING POSITIONED IN OVERLYING RELATIONSHIP WITH THE STRAP FOR ENGAGEMENT WITH THE OUTER SURFACE THEREOF AS THE STRAP IS TENSIONED BY THE DRIVEN TENSIONING MEMBER, AND A SECOND SUBSTANTIALLY STRAIGHT EDGE PART EXTENDING OUTWARDLY FROM A LATERAL END OF THE FIRST EDGE PART ENGAGEABLE WITH AW LATERAL EDGE OF THE TENSION STRAP AFTER THE TOOL AND HAS BEEN LATERALLY PIVOTED IN ONE PIVOTAL DIRECTION FOR DISPLACING THE FIRST EDGE PART OUT OF SAID OVERLYING RELATIONSHIP WITH THE STRAP WHEREBY THE SECOND EDGE PART PROVIDES A FULCRUM FOR THE PIVOTAL MOVEMENT OF THE TOOL IN THE OPPOSITE PIVOTAL DIRECTION FOR REMOVAL OF THE BASE FROM BETWEEN THE TENSIONED STRAP AND ARTICLES. 